Passion fruit (Passiflora edulis Sims) is an important horticultural crop in the tropics and subtropics, where it has great commercial potential due to high demand for fresh edible fruits and processed juice as well as source of raw materials in cosmetic industries. Genetic engineering shows great potential in passion fruit improvement and can compensate for the limitations of conventional breeding. Despite the success achieved in genetic modification of few passion fruit varieties, transgenic passion fruit production is still difficult for farmer-preferred cultivars. Therefore, it is important to establish a simple and fast Agrobacterium-mediated cell transformation of commercial hybrid passion fruit KPF4 (Passiflora edulis f. edulis × Passiflora edulis f. flavicarpa). In the present study, we have developed a simple and fast Agrobacterium-mediated transformation system for hybrid passion fruit KPF4 using leaf disc explants. Factors affecting the rate of transient beta (β)-glucuronidase (gusA) expression and consequently transformation efficiency were optimized as follows: Agrobacterium cell density with an OD600 of 0.5, 30 min infection time, 3 days of co-cultivation duration and the incorporation of 200 µM acetosyringone into Agrobacterium infection suspension medium. Using the optimized conditions, transgenic plants of KPF4 were produced within 2 months with an average transformation efficiency of 0.67%. The β-glucuronidase (GUS) histochemical staining confirmed the expression and integration of an intron-containing gusA gene into transformed leaf discs and transgenic plant lines of KPF4. The presence of gusA gene in the transgenic plants was confirmed by polymerase chain reaction (PCR). The results confirmed that the gusA gene was efficiently integrated into the passion fruit genome. The developed transformation protocol is simple and rapid and could be useful for functional genomic studies and transferring agronomically important traits into passion fruit hybrid KPF4. This study developed a method that can be used to transfer traits such as resistance to viral diseases, low fruit quality and short storage life. To the best of our knowledge, this is the first report on genetic transformation system for commercial passion fruit hybrid KPF4.

中文翻译：

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一种简单快速的农杆菌介导的百香果 KPF4 转化系统（Passiflora edulis f. edulis × Passiflora edulis f. flavicarpa）

百香果（Passiflora edulis Sims）是热带和亚热带地区重要的园艺作物，由于对新鲜食用水果和加工果汁的大量需求以及化妆品行业的原材料来源，具有巨大的商业潜力。基因工程在百香果改良方面显示出巨大潜力，可以弥补传统育种的局限性。尽管在少数百香果品种的基因改造方面取得了成功，但转基因百香果生产对于农民偏爱的品种来说仍然很困难。因此，建立一种简单、快速的农杆菌介导的商业杂交百香果 KPF4 (Passiflora edulis f. edulis × Passiflora edulis f. flavicarpa) 的细胞转化非常重要。在目前的研究中，我们使用叶盘外植体开发了一种简单快速的农杆菌介导的杂交百香果 KPF4 转化系统。影响瞬时 β (β)-葡糖醛酸酶 (gusA) 表达率和转化效率的因素优化如下：OD600 为 0.5 的农杆菌细胞密度、30 分钟感染时间、3 天共培养时间和掺入200 µM 乙酰丁香酮进入农杆菌感染悬浮培养基。使用优化的条件，KPF4转基因植物在2个月内产生，平均转化效率为0.67%。β-葡萄糖醛酸酶 (GUS) 组织化学染色证实了含有内含子的 gusA 基因在 KPF4 的转化叶盘和转基因植物系中的表达和整合。通过聚合酶链式反应(PCR)证实了转基因植物中gusA基因的存在。结果证实，gusA基因被有效整合到百香果基因组中。开发的转化方案简单快速，可用于功能基因组研究和将重要的农艺性状转移到百香果杂交种 KPF4 中。本研究开发了一种可用于转移性状的方法，例如对病毒病的抵抗力、果实质量低和贮藏期短。据我们所知，这是第一份关于商业百香果杂交种 KPF4 遗传转化系统的报告。开发的转化方案简单快速，可用于功能基因组研究和将重要的农艺性状转移到百香果杂交种 KPF4 中。本研究开发了一种可用于转移性状的方法，例如对病毒病的抵抗力、果实质量低和贮藏期短。据我们所知，这是第一份关于商业百香果杂交种 KPF4 遗传转化系统的报告。开发的转化方案简单快速，可用于功能基因组研究和将重要的农艺性状转移到百香果杂交种 KPF4 中。本研究开发了一种可用于转移性状的方法，例如对病毒病的抵抗力、果实质量低和贮藏期短。据我们所知，这是第一份关于商业百香果杂交种 KPF4 遗传转化系统的报告。